Motor driven propulsor of an aircraft

ABSTRACT

A motor driven propulsor of an aircraft includes magnets disposed in fan shrouds of fan blades connected with a fan hub, a stator having individual conductive coils in a nacelle located radially outside of the fan hub, and a distributed inverter assembly having several inverter power stages and gate drivers, each of the inverter power stages coupled with a separate gate driver of the gate drivers and a separate coil of the coils in the stator. Each of the gate drivers is configured to individually control supply of direct current to the corresponding inverter power stage. Each of the inverter power stages is configured to convert the direct current supplied to the inverter power stage to an alternating current that is supplied to the corresponding coil in the stator to rotate the magnets and the fan blades around a center line of the fan hub for propelling the aircraft.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/229,125, which was filed on 21 Dec. 2018, and the entire disclosureof which is incorporated herein by reference.

FIELD

The subject matter described herein relates to propulsion systems ofaircraft.

BACKGROUND

A traditional aircraft propulsor includes a gas turbine engine locatedat or within a fan hub of the propulsor. The gas turbine engine consumesfuel to rotate fan blades within a nacelle of the propulsor. Thisrotation of the fan blades generates thrust to propel the aircraft.

These types of propulsors suffer from several shortcomings. Theequipment needed to convert rotation of the turbine engine into rotationof the fan blades can require separate gearboxes, bearings, coolingsystems, and the like, all of which undesirably add to the weight of theaircraft. Additionally, gas turbine engines generate significantacoustic noise during operation, which can be undesirable to passengersof the aircraft.

Some proposed aircraft propulsors may include an electric motor toassist with rotation of the fan blades. These motors can help propel theaircraft after the gas turbine engine has provided significant thrustduring takeoff or lift off of the aircraft. But, some of these proposedmotors may not generate enough power for the thrust needed for takeoffor lift off of the aircraft. Additionally, some of these motors cangenerate significant heat that may require separate cooling systems tomaintain in an operative state. Moreover, the motors may not be able tooperate on their own and without associated gas turbine engines due tothe motors being less reliable than the gas turbine engines. Forexample, an inverter that supplies current to the coils of the motor mayfail, which prevents the motor from continuing to operate. Such a motorrequires an additional propulsor (e.g., the associated gas turbineengine) to prevent catastrophic failure of the aircraft.

BRIEF DESCRIPTION

In one embodiment, a motor driven propulsor of an aircraft is provided.The propulsor includes magnets disposed in fan shrouds of fan bladesconnected with a fan hub, a stator having individual conductive coils ina nacelle located radially outside of the fan hub, and a distributedinverter assembly having several inverter power stages and gate drivers,each of the inverter power stages coupled with a separate gate driver ofthe gate drivers and a separate coil of the coils in the stator. Each ofthe gate drivers is configured to individually control supply of directcurrent to the corresponding inverter power stage. Each of the inverterpower stages is configured to convert the direct current supplied to theinverter power stage to an alternating current that is supplied to thecorresponding coil in the stator to rotate the magnets and the fanblades around a center line of the fan hub for propelling the aircraft.

In one embodiment, a method for providing a motor driven propulsor of anaircraft is provided. The method includes placing magnets disposed infan shrouds of fan blades connected with a fan hub, positioning a statorhaving individual conductive coils in a nacelle located radially outsideof the fan hub, and coupling several inverter power stages of adistributed inverter assembly with several gate drivers. Each of theinverter power stages is coupled with a separate gate driver of the gatedrivers. The method also includes conductively coupling each of theinverter power stages with a different coil of the coils in the stator.Each of the gate drivers is coupled with a different inverter powerstage of the inverter power stages to individually control supply ofdirect current to the corresponding inverter power stage. Each of theinverter power stages is coupled with the corresponding gate driver andthe corresponding coil to convert the direct current supplied to theinverter power stage to an alternating current that is supplied to thecorresponding coil in the stator to rotate the magnets and the fanblades around a center line of the fan hub for propelling the aircraft.

In one embodiment, a motor driven propulsor includes magnets disposed infan shrouds of fan blades connected with a fan hub, a stator havingindividual conductive coils in a nacelle located radially outside of thefan hub, and a distributed inverter assembly having several inverterpower stages. Each of the inverter power stages is close coupled with aseparate coil of the coils in the stator. Each of the inverter powerstages is configured to power the corresponding coil in the stator torotate the magnets and the fan blades around a center line of the fanhub for generating a propulsive force. The inverter power stages areseparately coupled with the coils in the stator such that one or moreinverter power stages continue powering the corresponding coils tocontinue generating the propulsive force after failure of at least oneof the inverter power stages.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 provides a top view of an aircraft as may incorporate variousembodiments of the inventive subject matter described herein.

FIG. 2 illustrates a front view of one embodiment of a propulsor shownin FIG. 1.

FIG. 3 illustrates a cross-sectional view of one embodiment of thepropulsor shown in FIG. 2.

FIG. 4 illustrates part of one embodiment of a motor shown in FIG. 2.

FIG. 5 illustrates one embodiment of a distributed inverter assembly ofthe propulsor shown in FIG. 2.

FIG. 6 also illustrates the distributed inverter assembly shown in FIG.5.

FIG. 7 illustrates another embodiment of a fan shroud and a fan blade ofthe propulsor shown in FIG. 2.

FIG. 8 illustrates another embodiment of a fan shroud and a fan blade ofthe propulsor shown in FIG. 2.

FIG. 9 illustrates a flowchart of one embodiment of a method forproviding a motor-driven propulsor of an aircraft.

DETAILED DESCRIPTION

Embodiments of the subject matter described herein relate to motordriven propulsors of aircraft. In one embodiment, a fan of a turbofanengine is combined with an electric motor (also referred to as agenerator). The fan can be combined with the motor without alsoconnecting the turbofan or a turbine engine with the fan (or any otherfan of the same aircraft, in one example). The electrical motor islocated on outside of the fan in a nacelle of the aircraft. A shroudedfan is provided with permanent magnets embedded in the shroud of fanblades of the fan. The stator of the motor is provided in the nacelle. Aclose coupled distributed inverter can be provided to providealternating current (AC) power to coils of the stator (that are in thenacelle). This distributed inverter also can be in the nacelle. Theexternal and internal surfaces of the nacelle may be used to dissipateheat of the electric motor to air flowing inside and outside the nacelleto assist with cooling and rejecting heat from the motor and associatedcomponents. One or more gate drivers are provided to individuallycontrol power stages of the distributed inverter using a high-speedcommunication channel, such as via optical fibers, in one embodiment. Adirect current (DC) power bus can be provided around the nacelle toprovide power to the distributed power stages of the inverter.

By placing the electrical motor directly on the shroud of the fan,significant savings of weight are achieved relative to turbofanpropulsors, as the need for separate or additional gearboxes, bearings,cooling systems, and housings are eliminated. Significant weight savingscan be achieved by utilizing the motor at the highest shear gapvelocities obtainable by the motor. Use of an electric motor instead ofa turbofan also significantly reduces the acoustic noise generated byoperation of the propulsor.

While one or more embodiments described herein provide the stator andstator coils radially outward of a hub to which the fan blades of thepropulsor are connected (e.g., relative to an axis of rotation or centerline of the hub of the propulsor), alternatively, the stator and coilscan be placed inside the hub to rotate the fan blades.

FIG. 1 provides a top view of an aircraft 10 as may incorporate variousembodiments of the inventive subject matter described herein. Theaircraft 10 defines a longitudinal centerline 14 that extendstherethrough, a lateral direction L, a forward end 16, and an aft end18. The aircraft 10 includes a fuselage 12 that longitudinally extendsfrom the forward end 16 of the aircraft 10 to the aft end 18 of theaircraft 10, and a wing assembly including a port side and a starboardside. The port side of the wing assembly is a first, port side wing 20,and the starboard side of the wing assembly is a second, starboard sidewing 22. The first and second wings 20, 22 each extend laterally outwardwith respect to the longitudinal centerline 14. The first wing 20 and aportion of the fuselage 12 together define a first side 24 of theaircraft 10, and the second wing 22 and another portion of the fuselage12 together define a second side 26 of the aircraft 10. In theillustrated embodiment, the first side 24 of the aircraft 10 can bereferred to as the port side of the aircraft 10, and the second side 26of the aircraft 10 can be referred to as the starboard side of theaircraft 10.

Each of the wings 20, 22 includes one or more leading edge flaps 28 andone or more trailing edge flaps 30. The aircraft 10 further includes avertical stabilizer 32 having a rudder flap (not shown) for yaw control,and a pair of horizontal stabilizers 34, each having an elevator flap 36for pitch control. The fuselage 12 additionally includes an outersurface or skin 38. Alternatively, the aircraft 10 may additionally oralternatively include any other suitable configuration. For example, inother embodiments, the aircraft 10 may include any other configurationof stabilizer.

The aircraft 10 includes a propulsion system 50 having a first propulsor200 and a second propulsor 200. As shown, each of the propulsors 200 isconfigured as an under-wing mounted propulsor and may be disposed in ormay include a corresponding nacelle 202 of the aircraft 10. Onepropulsor 200 is mounted, or configured to be mounted, to the first side24 of the aircraft 10, such as to the first wing 20 of the aircraft 10.The propulsion system 50 includes an electrical power bus 58 to supplycurrent to the propulsors 200. The propulsion system 50 may include oneor more energy storage devices 55 (such as one or more batteries orother electrical energy storage devices) electrically connected to theelectrical power bus 58 for providing electrical power to the propulsors200. As shown, the aircraft 10 does not include any turbine engine orother fuel-consuming engine that operates to generate thrust to propelthe aircraft 10. Optionally, the aircraft 10 can include one or moreturbine engines, turbofans, or the like, for providing thrust and/orgenerating electric current to power the propulsors 200.

FIG. 2 illustrates a front view of one embodiment of one of thepropulsors 200 shown in FIG. 1. FIG. 3 illustrates a cross-sectionalview of one embodiment of the propulsor 200 shown in FIG. 2. Thepropulsor 200 includes a spinner 204 located within the nacelle 202. Thespinner 204 is coupled with several fan blades 206 that extend radiallyoutward from the spinner 204. These fan blades 206 also extend radiallyoutward from a center line 226 or axis of rotation of the spinner 204.The spinner 204 houses a fan hub 208 to which inner ends 210 of the fanblades 206 are coupled. Outlet guide vanes 212 may radially extend fromthe spinner 204 toward the nacelle 202 and may be connected with the fanblades 206 by thrust bearings 214.

A rim-driven motor 216 includes a stator 218 that is at least partiallydisposed within the nacelle 202. The stator 218 can be positioned alongan inner surface 220 of the nacelle 202 or closer to the inner surface220 of the nacelle 202 than an opposite outer surface 222 of the nacelle202. As shown in FIG. 3, the stator 218 extends around or encircles thecenter line 226 of the spinner 204 and fan hub 208. The motor 216 alsoincludes magnets, such as permanent magnets, disposed in fan shrouds 224of the fan blades 206. The fan shrouds 224 are located at or on ends ofthe fan blades 206 that are opposite the inner ends 210. For example,the fan shrouds 224 that include the magnets may be located closer tothe nacelle 202 than the spinner 204 or fan hub 208. As describedherein, the stator 218 includes conductive coils that are powered byseparate inverter power stages of a distributed inverter of thepropulsor 200 to rotate the magnets in the fan shrouds 224 (and,therefore, rotate the fan blades 206) to generate thrust to the aircraft10.

As shown, the nacelle 202 is located radially outside of the spinner 204and the fan hub 208 (relative to the center line 226) so that air flow228 can pass between the spinner 204 and the inner surface 220 of thenacelle 202. Additional air flow can extend over the outer surface 222of the nacelle 202. This air flow can help cool and/or reject heat fromthe components of the propulsor 200. For example, the coils, buses,inverter power stages, gate drivers, and the like, that are describedherein may become heated during operation of the propulsor 200 due tothe electric current flowing and/or induced in one or more of thesecomponents. Placing these components in the nacelle 202 and in thermalcontact with the surfaces 220, 222 of the nacelle 202 provide thecomponents with a much larger surface area over which to dissipate orreject heat into the external environment. For example, placing thesecomponents inside the spinner 204 or hub 208 can significantly decreasethe surface area through which thermal energy can be transferred to theexternal environment relative to the much larger surface area of theinner and outer surfaces 220, 222 of the nacelle 202.

FIG. 4 illustrates part of one embodiment of the motor 216 shown in FIG.2. The portion of the motor 216 that is shown in FIG. 3 includes one ofseveral conductive coils 400 through which AC is conducted totemporarily induce magnetic fields. These magnetic fields interact withthe permanent magnetic fields provided by one or more permanent magnets402 that are embedded in the shroud 224 of a fan blade 206. Thisinteraction can move the fan blade 206 to rotate the spinner 204 aroundthe center line 226 to generate thrust for propelling the aircraft 10.

The coil 400 is conductively coupled with one of several inverter powerstages 404 of a distributed inverter assembly (described below) by oneor more conductive buses 406. Alternatively, each of the inverter powerstages 404 can represent an inverter. In one embodiment, the coils 400are closely coupled with the inverter power stages 404. The conductivebus 406 may represent part of the power bus 58 shown in FIG. 1 or mayrepresent another conductive bus. The inverter power stage 404 convertsDC received from a source (e.g., the energy storage device 55 via thepower bus 58) into a single phase of AC. This single phase of AC isconducted via the bus 406 to and through the coil 400 to create thetemporary magnetic fields described above.

FIGS. 5 and 6 illustrate one embodiment of a distributed inverterassembly 500 of the propulsor 200. The distributed inverter assembly 500includes several circuit sets 502 of the inverter power stages 404, gatedrivers 504 (not shown in FIG. 6), and the coils 400. Only a singleinverter power stage 404 is shown in FIG. 5, but several of the inverterpower stages 404 are provided in one embodiment.

In the illustrated embodiment, each set 502 of the distributed inverterassembly 500 includes an inverter power stage 404 separately controlledby a separate gate driver 504 and separately coupled with a differentcoil 400 in the stator 218. Stated differently, each coil 400 isseparately powered with a different, single inverter power stage 404instead of multiple coils 400 receiving one or more phases of AC fromthe same inverter power stage 404. Alternatively, two or more, but fewerthan all, of the coils 400 may be connected with the same inverter powerstage 404 such that multiple, but not all, of the coils 400 are poweredby the phase of AC supplied from the same inverter power stage 404. Thecoils 400 may be separate from each other such that current conducted inone coil 400 is not conducted to any other coil 400.

Each inverter power stage 404 is connected with a separate gate driver504. Alternatively, two or more inverter power stages 404 can beconnected with the same gate driver 504. The inverter power stage 404can be connected with the gate driver 504 by one or more opticalconnections 518, such as by one or more optical fibers. The use ofoptical fibers can reduce the effects of electromagnetic interference onthe several gate drivers 504 communicating with the several inverterpower stages 404 to ensure that the inverter power stages 404 arecontrolled to rotate the fan blades 206. Alternatively, the inverterpower stages 404 can be connected with the gate drivers 504 usingconductive connections (e.g., buses) or other types of connections.

The gate driver 504 is connected with DC buses 506, 508, 510, includinga positive DC bus 506, a negative DC bus 508, and a neutral bus 510.Each gate driver 504 can include a connection 512 with the positive DCbus 506 that does not connect with the negative DC bus 508 or theneutral bus 510, a connection 514 with the negative DC bus 508 that doesnot connect with the positive DC bus 506 or the neutral bus 510, and aconnection 516 with the neutral bus 510 that does not connect with thepositive DC bus 506 or the negative DC bus 508.

The buses 506, 508, 510 can represent part of the power bus 58 shown inFIG. 1 to receive DC from the energy storage device 55, can be connectedwith the power bus 58 to receive DC from the energy storage device 55,or can represent other conductive bodies. While only a single set of theconnections 512, 514, 516 between the gate drivers 504 and the buses506, 508, 510 are shown in FIG. 6, each of the gate drivers 504 caninclude a set of the connections 512, 514, 516 with the correspondingbuses 506, 508, 510. As shown in FIGS. 5 and 6, multiple or all gatedrivers 504 can be connected with the same (e.g., common) positive DCbus 506, the same negative DC bus 508, and the same neutral bus 510.Alternatively, two or more of the gate drivers 504 can be connected withdifferent positive DC buses 506, different negative DC buses 508, and/ordifferent neutral buses 510.

The gate driver 504 controls conduction of positive DC from the positiveDC bus 506, conduction of negative DC from the negative DC bus 508, andconnects the inverter power stage 404 with the neutral bus 510 so thatthe inverter power stage 404 can convert the positive and negative DCinto a single phase of AC current that is conducted to and through thecorresponding coil 400. As described above, this helps drive the magnets402 to rotate the fan blades 206 around the center line 226. The gatedrivers 504 can be controlled by control signals sent from thecontroller 62, which may be based on manually input and/or automaticallydetermined throttle instructions or directives for the aircraft 10.

As shown in FIG. 6, the coils 400, inverter power stages 404, gatedrivers 504, and buses 406, 506, 508, 510 can be disposed inside thenacelle 202 between the inner and outer surfaces 220, 222 of the nacelle202. These components may be in thermal contact with the surfaces 220and/or 222 of the nacelle 202 so that heat generated by these componentscan be transferred to the surfaces 220 and/or 222 and dissipated outsideof the propulsor 200.

The separate coils 400, separate inverter power stages 404, and separategate drivers 504 can provide for increased reliability of the motor 216relative to other non-distributed motor designs. For example, thefailure of one or some (but not all) coils 400, the failure of one orsome (but not all) inverter power stages 404, and/or the failure of oneor some (but not all) gate drivers 504 does not prevent the motor 216from continuing to rotate the fan blades 206. The failure an inverterpower stage 404, the failure of a gate driver 504, the interruption orbreak of a connection between the inverter power stage 404 and the coil400 that was connected with the inverter power stage 404, and/or theinterruption or break of the conductive loop formed by the coil 400 mayprevent that inverter power stage 404, that gate driver 504, and/or thatcoil 400 from operating to generate a magnetic field that rotates thefan blades 206. But, this failure or interruption will not prevent orstop other gate drivers 504, corresponding inverter power stages 404,and corresponding coils 400 from operating to generate magnetic fieldsthat rotate the fan blades 206. While the motor 216 may operate toproduce less peak power in such a failure or interrupted state, themotor 216 may continue to operate to generate thrust to keep propellingthe aircraft 10.

In the embodiment shown in FIG. 4, the magnets 402 are disposed withinthe fan shrouds 224 of the fan blades 206 in locations that are radiallyinside of the inner surface 220 of the nacelle 202. For example, themagnets 402 can be located between the inner surface 220 of the nacelle202 and the center line 226.

FIG. 7 illustrates another embodiment of a fan shroud 724 of the fanblades 206. The fan shrouds 724 can be coupled with the same fan blades206 as the shroud 224. A nacelle 702 shown in FIG. 7 can be used inplace of the nacelle 202 shown in FIGS. 2, 3, 4, and 6. One differencebetween the nacelle 702 and the nacelle 202 is that the nacelle 702includes a recessed channel 730. This channel 730 can extend around thecenter line 226 of the fan hub 208 or spinner 204 such that the channel730 extends along a path that encircles the center line 226 around andradially outside of the fan blades 206.

The fan shroud 724 includes a radial extension 732 that outwardlyprotrudes from the outer end of the fan shroud 724 away from the centerline 226. The radial extension 732 is shaped to fit and move within thechannel 730 in the nacelle 702 without contacting or rubbing against anysurface of the nacelle 702. The magnets 402 can be located on oppositesides of the extension 732 such that the magnets 402 face away from eachother. Conductive coils 700 located in a stator 718 can be used in placeof the coils 400 in the stator 218. The cross-sectional view shown inFIG. 7 illustrates a plane that bisects each coil 700. As describedabove, each coil 700 can be separately closely coupled with a differentinverter power stage 404, which can be separately coupled with adifferent gate driver 504.

The stator 718 can include several coils 700 located at differentpositions in the path that circumferentially extends around the centerline 226. For example, the stator 718 can include more than just asingle coil 700 on each side of the channel 730. In the illustratedembodiment, the stator 718 includes coils 700 on both sides of thechannel 730. Alternatively, the stator 718 may have coils 700 on onlyone side of the channel 730.

FIG. 8 illustrates another embodiment of a fan shroud 824 of the fanblades 206. The fan shrouds 824 can be coupled with the same fan blades206 as the shroud 224. A nacelle 802 shown in FIG. 8 can be used inplace of the nacelle 202 shown in FIGS. 2, 3, 4, and 6. One differencebetween the nacelle 802 and the nacelle 202 is that the nacelle 802includes two recessed channels 830. Each of the channels 830 can extendaround the center line 226 of the fan hub 208 or spinner 204 such thateach channel 830 extends along a different path that encircles thecenter line 226 around and radially outside of the fan blades 206.

The fan shroud 824 includes multiple radial extensions 832 thatoutwardly protrude from the outer end of the fan shroud 824 away fromthe center line 226. Each of the radial extensions 832 is shaped to fitand move within a different one of the channels 830 in the nacelle 802without contacting or rubbing against any surface of the nacelle 802.One or more magnets 402 can be located in each of the extensions 832 onopposite sides of a stator 818 in the nacelle 802 such that the magnets402 face each other. Conductive coils 800 located in the stator 818 canbe used in place of the coils 400 in the stator 218. As shown, the coils800 are located between the magnets 402 in the stator 818. Thecross-sectional view shown in FIG. 8 illustrates a plane that bisectseach coil 800. As described above, each coil 800 can be separatelyclosely coupled with a different inverter power stage 404, which can beseparately coupled with a different gate driver 504. The stator 818 caninclude several coils 800 located at different positions in the paththat circumferentially extends around the center line 226. For example,the stator 818 can include more than just a single coil 800 facing eachmagnet 402.

FIG. 9 illustrates a flowchart of one embodiment of a method 900 forproviding a motor-driven propulsor of an aircraft. The method 900 can beused to create one or more embodiments of the propulsors 200 describedherein. The operations of the method 900 can be performed in a differentorder than what is shown in the flowchart. For example, the order of twoor more of the operations may be switched with each other and/or two ormore of the operations may be performed concurrently and/orsimultaneously.

At 902, magnets are placed into fan shrouds of fan blades that areconnected with a fan hub. The magnets can be permanent magnets locatedin fan shrouds that are radially inside of a nacelle of the aircraft.The fan shrouds may be closer to the nacelle than the fan hub and mayface the inner surface of the nacelle.

At 904, a stator is positioned in the nacelle of the aircraft. Forexample, conductive coils may be positioned in a housing that extendsaround and encircles the fan blades, the spinner, and the fan hub. Theconductive coils can be separate from each other such that currentconducted in one coil is not conducted from that coil to another coil.

At 906, several inverter power stages of a distributed inverter assemblyare coupled with several gate drivers. Each of the inverter power stagescan be coupled with a separate gate driver of the gate drivers. Theconnections between the inverter power stages and the gate drivers canbe made using an optical connection, such as an optical fiber, to allowfor the gate drivers to control the inverter power stages using lightsignals. Alternatively, the inverter power stages can be conductivelycoupled with the gate drivers.

At 908, the inverter power stages are conductively coupled with thecoils in the stator. Each inverter power stage can be conductivelycoupled with a different coil so that failure of a gate driver, inverterpower stage, coil, or connection therebetween does not prevent othercoils inverter power stages, or gate drivers from continuing to operateto generate thrust by rotating the fan blades.

In one embodiment, a motor driven propulsor of an aircraft is provided.The propulsor includes magnets disposed in fan shrouds of fan bladesconnected with a fan hub, a stator having individual conductive coils ina nacelle located radially outside of the fan hub, and a distributedinverter assembly having several inverter power stages and gate drivers,each of the inverter power stages coupled with a separate gate driver ofthe gate drivers and a separate coil of the coils in the stator. Each ofthe gate drivers is configured to individually control supply of directcurrent to the corresponding inverter power stage. Each of the inverterpower stages is configured to convert the direct current supplied to theinverter power stage to an alternating current that is supplied to thecorresponding coil in the stator to rotate the magnets and the fanblades around a center line of the fan hub for propelling the aircraft.

Optionally, each of the inverter power stages is close coupled with thecorresponding coil to which the inverter power stage is conductivelyconnected. The nacelle can be configured to transfer heat generated inthe coils of the stator over a large surface area that is outside of thefan blades and the fan hub. The coils of the stator and the inverterpower stages may be thermally coupled with a radially inward surface ofthe nacelle and with a radially outward surface of the nacelle.

Optionally, the inverter power stages and the gate drivers are coupledwith a direct current bus, and the inverter power stages, the gatedrivers, and the direct current bus are located within the nacelle. Thegate drivers can all be connected to a common positive direct currentbus, a common negative direct current bus, and a common neutral bus. Themagnets may be disposed within the fan shrouds of the fan blades inlocations that are radially inside of an inner surface of the nacelle.

Optionally, the nacelle includes a channel that extends around thecenter line of the fan hub. The magnets can be located in radialprotrusions of the fan shrouds that radially project away from thecenter line of the fan hub and into the channel in the nacelle. Theconductive coils in the stator may be located on opposite sides of thechannel in the nacelle.

Optionally, the nacelle includes channels that extend around the centerline of the fan hub. The magnets can be located in radial protrusions ofthe fan shrouds that radially project away from the center line of thefan hub and into the channels in the nacelle. The conductive coils inthe stator may be located between the channels in the nacelle.

Optionally, the inverter power stages are connected with the gatedrivers by optical fibers and the gate drivers are configured to controlsupply of the direct current to the inverter power stages using controlsignals communicated via the optical fibers.

In one embodiment, a method for providing a motor driven propulsor of anaircraft is provided. The method includes placing magnets disposed infan shrouds of fan blades connected with a fan hub, positioning a statorhaving individual conductive coils in a nacelle located radially outsideof the fan hub, and coupling several inverter power stages of adistributed inverter assembly with several gate drivers. Each of theinverter power stages is coupled with a separate gate driver of the gatedrivers. The method also includes conductively coupling each of theinverter power stages with a different coil of the coils in the stator.Each of the gate drivers is coupled with a different inverter powerstage of the inverter power stages to individually control supply ofdirect current to the corresponding inverter power stage. Each of theinverter power stages is coupled with the corresponding gate driver andthe corresponding coil to convert the direct current supplied to theinverter power stage to an alternating current that is supplied to thecorresponding coil in the stator to rotate the magnets and the fanblades around a center line of the fan hub for propelling the aircraft.

Optionally, conductively coupling each of the inverter power stages withthe different coil includes close coupling the inverter power stage withthe corresponding coil. The coils of the stator can be positioned in thenacelle and the inverter power stages are coupled with the coils suchthat the coils and the inverter power stages are thermally coupled witha radially inward surface of the nacelle and with a radially outwardsurface of the nacelle.

The method also can include coupling the inverter power stages and thegate drivers with a direct current bus such that the inverter powerstages, the gate drivers, and the direct current bus are located withinthe nacelle. The nacelle may include one or more channels that extendaround the center line of the fan hub, and wherein the magnets arepositioned in radial protrusions of the fan shrouds that radiallyproject away from the center line of the fan hub and into the one ormore channels in the nacelle. Optionally, the inverter power stages arecoupled with the gate drivers by optical fibers.

In one embodiment, a motor driven propulsor includes magnets disposed infan shrouds of fan blades connected with a fan hub, a stator havingindividual conductive coils in a nacelle located radially outside of thefan hub, and a distributed inverter assembly having several inverterpower stages. Each of the inverter power stages is close coupled with aseparate coil of the coils in the stator. Each of the inverter powerstages is configured to power the corresponding coil in the stator torotate the magnets and the fan blades around a center line of the fanhub for generating a propulsive force. The inverter power stages areseparately coupled with the coils in the stator such that one or moreinverter power stages continue powering the corresponding coils tocontinue generating the propulsive force after failure of at least oneof the inverter power stages.

Optionally, the coils of the stator and the inverter power stages arethermally coupled with a radially inward surface of an aircraft nacelleand with a radially outward surface of the nacelle.

As used herein, an element or step recited in the singular and proceededwith the word “a” or “an” should be understood as not excluding pluralof said elements or steps, unless such exclusion is explicitly stated.Furthermore, references to “one embodiment” of the presently describedinventive subject matter are not intended to be interpreted as excludingthe existence of additional embodiments that also incorporate therecited features. Moreover, unless explicitly stated to the contrary,embodiments “comprising,” “including,” or “having” (or like terms) anelement, which has a particular property or a plurality of elements witha particular property, may include additional such elements that do nothave the particular property.

As used herein, terms such as “system” or “controller” may includehardware and/or software that operate(s) to perform one or morefunctions. For example, a system or controller may include a computerprocessor or other logic-based device that performs operations based oninstructions stored on a tangible and non-transitory computer readablestorage medium, such as a computer memory. Alternatively, a system orcontroller may include a hard-wired device that performs operationsbased on hard-wired logic of the device. The systems and controllersshown in the figures may represent the hardware that operates based onsoftware or hardwired instructions, the software that directs hardwareto perform the operations, or a combination thereof.

As used herein, terms such as “operably connected,” “operativelyconnected,” “operably coupled,” “operatively coupled” and the likeindicate that two or more components are connected in a manner thatenables or allows at least one of the components to carry out adesignated function. For example, when two or more components areoperably connected, one or more connections (electrical and/or wirelessconnections) may exist that allow the components to communicate witheach other, that allow one component to control another component, thatallow each component to control the other component, and/or that enableat least one of the components to operate in a designated manner.

It is to be understood that the subject matter described herein is notlimited in its application to the details of construction and thearrangement of elements set forth in the description herein orillustrated in the drawings hereof. The subject matter described hereinis capable of other embodiments and of being practiced or of beingcarried out in various ways. Also, it is to be understood that thephraseology and terminology used herein is for the purpose ofdescription and should not be regarded as limiting. The use of“including,” “comprising,” or “having” and variations thereof herein ismeant to encompass the items listed thereafter and equivalents thereofas well as additional items.

It is to be understood that the above description is intended to beillustrative, and not restrictive. For example, the above-describedembodiments (and/or aspects thereof) may be used in combination witheach other. In addition, many modifications may be made to adapt aparticular situation or material to the teachings of the presentlydescribed subject matter without departing from its scope. While thedimensions, types of materials and coatings described herein areintended to define the parameters of the disclosed subject matter, theyare by no means limiting and are exemplary embodiments. Many otherembodiments will be apparent to one of ordinary skill in the art uponreviewing the above description. The scope of the inventive subjectmatter should, therefore, be determined with reference to the appendedclaims, along with the full scope of equivalents to which such claimsare entitled. In the appended claims, the terms “including” and “inwhich” are used as the plain-English equivalents of the respective terms“comprising” and “wherein.” Moreover, in the following claims, the terms“first,” “second,” and “third,” etc. are used merely as labels, and arenot intended to impose numerical requirements on their objects. Further,the limitations of the following claims are not written inmeans-plus-function format and are not intended to be interpreted basedon 35 U.S.C. § 112(f), unless and until such claim limitations expresslyuse the phrase “means for” followed by a statement of function void offurther structure.

This written description uses examples to disclose several embodimentsof the inventive subject matter, and also to enable one of ordinaryskill in the art to practice the embodiments of inventive subjectmatter, including making and using any devices or systems and performingany incorporated methods. The patentable scope of the inventive subjectmatter is defined by the claims, and may include other examples thatoccur to one of ordinary skill in the art. Such other examples areintended to be within the scope of the claims if they have structuralelements that do not differ from the literal language of the claims, orif they include equivalent structural elements with insubstantialdifferences from the literal languages of the claims.

What is claimed is:
 1. A motor driven propulsor of an aircraft, themotor driven propulsor comprising: magnets disposed in fan shrouds offan blades connected with a fan hub; a stator having individualconductive coils in a nacelle located radially outside of the fan hub;and a distributed inverter assembly having several inverter power stagesand gate drivers, the inverter power stages coupled with the gatedrivers and the coils in the stator, wherein the gate drivers areconfigured to control supply of direct current to the inverter powerstages, and the inverter power stages are configured to convert thedirect current supplied to the inverter power stages to alternatingcurrent that is supplied to the coils in the stator to rotate themagnets and the fan blades around a center line of the fan hub forpropelling the aircraft.
 2. The motor driven propulsor of claim 1,wherein the inverter power stages are close coupled with the coils. 3.The motor driven propulsor of claim 1, wherein the nacelle is configuredto transfer heat generated in the coils of the stator over a largesurface area that is outside of the fan blades and the fan hub.
 4. Themotor driven propulsor of claim 1, wherein the coils of the stator andthe inverter power stages are thermally coupled with a radially inwardsurface of the nacelle and with a radially outward surface of thenacelle.
 5. The motor driven propulsor of claim 1, wherein the inverterpower stages and the gate drivers are coupled with a direct current bus,and the inverter power stages, the gate drivers, and the direct currentbus are located within the nacelle.
 6. The motor driven propulsor ofclaim 1, wherein the gate drivers are connected to a common positivedirect current bus, a common negative direct current bus, and a commonneutral bus.
 7. The motor driven propulsor of claim 1, wherein themagnets are disposed within the fan shrouds of the fan blades inlocations that are radially inside of an inner surface of the nacelle.8. The motor driven propulsor of claim 1, wherein the nacelle includes achannel that extends around the center line of the fan hub, and whereinthe magnets are located in radial protrusions of the fan shrouds thatradially project away from the center line of the fan hub and into thechannel in the nacelle.
 9. The motor driven propulsor of claim 8,wherein the conductive coils in the stator are located on opposite sidesof the channel in the nacelle.
 10. The motor driven propulsor of claim1, wherein the nacelle includes channels that extend around the centerline of the fan hub, and wherein the magnets are located in radialprotrusions of the fan shrouds that radially project away from thecenter line of the fan hub and into the channels in the nacelle.
 11. Themotor driven propulsor of claim 10, wherein the conductive coils in thestator are located between the channels in the nacelle.
 12. The motordriven propulsor of claim 1, wherein the inverter power stages areconnected with the gate drivers by optical fibers and the gate driversare configured to control supply of the direct current to the inverterpower stages using control signals communicated via the optical fibers.13. A method for providing a motor driven propulsor of an aircraft, themethod comprising: placing magnets disposed in fan shrouds of fan bladesconnected with a fan hub; positioning a stator having individualconductive coils in a nacelle located radially outside of the fan hub;coupling several inverter power stages of a distributed inverterassembly with several gate drivers, the inverter power stages coupledwith the gate drivers; conductively coupling the inverter power stageswith the coils in the stator, wherein the gate drivers are coupled withthe inverter power stages to control supply of direct current to theinverter power stages, and the inverter power stages are coupled withthe gate drivers and the coils to convert the direct current supplied tothe inverter power stages to alternating current that is supplied to thecoils in the stator to rotate the magnets and the fan blades around acenter line of the fan hub for propelling the aircraft.
 14. The methodof claim 13, wherein conductively coupling the inverter power stageswith the coils includes close coupling the inverter power stages withthe coils.
 15. The method of claim 13, wherein the coils of the statorare positioned in the nacelle and the inverter power stages are coupledwith the coils such that the coils and the inverter power stages arethermally coupled with a radially inward surface of the nacelle and witha radially outward surface of the nacelle.
 16. The method of claim 13,further comprising: coupling the inverter power stages and the gatedrivers with a direct current bus such that the inverter power stages,the gate drivers, and the direct current bus are located within thenacelle.
 17. The method of claim 13, wherein the nacelle includes one ormore channels that extend around the center line of the fan hub, andwherein the magnets are positioned in radial protrusions of the fanshrouds that radially project away from the center line of the fan huband into the one or more channels in the nacelle.
 18. The method ofclaim 13, wherein the inverter power stages are coupled with the gatedrivers by optical fibers.
 19. A motor driven propulsor comprising:magnets disposed in fan shrouds of fan blades connected with a fan hub;a stator having individual conductive coils in a nacelle locatedradially outside of the fan hub; and a distributed inverter assemblyhaving several inverter power stages, the inverter power stages closecoupled with the coils in the stator, wherein the inverter power stagesare configured to power the corresponding coil in the stator to rotatethe magnets and the fan blades around a center line of the fan hub forgenerating a propulsive force, and wherein the inverter power stages arecoupled with the coils in the stator such that one or more inverterpower stages continue powering the coils to continue generating thepropulsive force after failure of at least one of the inverter powerstages.
 20. The motor driven propulsor of claim 19, wherein the coils ofthe stator and the inverter power stages are thermally coupled with aradially inward surface of an aircraft nacelle and with a radiallyoutward surface of the nacelle.